The present invention relates to structural panels having a cellular core sandwiched between metal face sheets and surrounded by a frame, and to building structures that incorporate such panels.
The vast majority of residential building structures in the United States are currently constructed from a wooden frame composed of many pieces of lumber nailed to one another. This type of construction, often referred to as xe2x80x9cstickxe2x80x9d construction, is currently favored in part because of the ready availability of lumber, but its popularity also has to do with a lack of practical alternatives. The widespread use of stick construction exists despite known disadvantages of stick construction in comparison with alternative types of construction that have been developed. For instance, steel-frame structures, which are increasingly being used in commercial and in some residential structures, have a much greater strength potential than wood-frame structures, are not susceptible to rot or insect damage, and have a lower material cost than wood-frame structures.
Even though these advantages of steel-frame construction are known, the construction industry, particularly in residential construction, has not been quick to switch to steel-frame construction. The industry""s resistance to change is due in large part to a lack of skilled workers who have experience in steel-frame construction. The resistance is also due, however, to the high labor cost that is incurred in assembling a steel-frame structure. Conventional steel-frame structures are assembled by using a very large number of screws for fixing the steel framing members to one another. The process of inserting screws is much slower than nailing, and so it typically takes considerably longer to assemble a traditional steel frame than to assemble a wood frame.
The present invention relates to building materials and structures representing alternatives to conventional stick construction. Various alternative building materials and techniques have been proposed in the prior art. For instance, many types of building panels having a cellular core and metal face sheets have been proposed for use in the construction of various types of building structures. To date, however, the widespread use of such panels for constructing structures such as residential houses has not occurred. This is at least partly because of the difficulty of attaching the panels to one another and to other parts of the structure. The panel-to-panel and panel-to-structure attachments desirably should avoid penetrating the face sheets with fasteners, since penetrations of the face sheets in the region of the core can allow water to infiltrate the core.
The present invention seeks to improve upon traditional stick construction and to overcome the above-noted and other problems associated with constructing building structures from steel frames and/or cellular-core panels, by providing a panel and a building structure that facilitate assembly of the structure in a relatively simple manner without requiring a very large number of screws or other fasteners. The panel and structure also can achieve a higher strength than conventional wood-frame structures.
A panel in accordance with one embodiment of the invention comprises a core of cellular material, such as a honeycomb material, having a metal face sheet bonded to each of the opposite faces of the core. A side frame member is attached between the longitudinal edges of the face sheets along each of the two longitudinal edges of the core. Each of the side frame members defines a longitudinally extending protrusion and also defines a longitudinally extending recessed channel. The protrusion of each side frame member is aligned in the thickness direction of the panel with the channel of the other side frame member. Accordingly, two panels can be positioned with one side frame member of one panel opposing a side frame member of the other panel, and the protrusion of each side frame member can be inserted into the channel of the other side frame member, thus forming an interlocking panel joint between the panels. The interlocking side frame members prevent relative movement between the panels in at least the thickness direction. Preferably, the protrusions and channels extend along substantially the full longitudinal length of the panel. For convenience of manufacture, it is preferred to form the side frame members by roll-forming sheet metal.
In preferred embodiments of the invention, the side frame members and the face sheets of the panel form interlocking connections. This is preferably achieved by forming an edge of a side frame member and the adjacent edge of the face sheet such that at least one of the edges is hook-shaped and engages the other edge.
The panel preferably also includes end frame members that extend along the transversely extending edges of the core and are affixed between the ends of the side frame members to form a frame enclosing the core. The end frame members can also form interlocking connections with at least one of the face sheets. Preferably, each end frame member defines an outwardly projecting flange that extends beyond the transverse edge of the core for attaching the panel to a structure. The panel can also include an additional reinforcing member that is attached between two of the frame members and divides the core into two separate portions. The end frame and reinforcing members advantageously comprise roll-formed sheet metal members.
In one embodiment, the panel comprises a roof panel for a roof of a building, and one face sheet forms an upper surface of the roof and has a configuration and appearance for simulating a conventional type of roofing material. The upper face sheet can be configured, for example, to simulate the appearance of shingles. Alternatively, the upper face sheet can have upstanding ridge-shaped portions for simulating standing seams such as are present on conventional metal roofs. The panel in this embodiment includes at least one ridge-shaped portion that defines a hollow cavity between the face sheet and the core. Preferably, the cavity of the ridge-shaped portion is filled with adhesive, and the adhesive also is disposed between the entire face of the core and the face sheet for bonding the face sheet to the core. By filling the cavity of the ridge-shaped portion with adhesive, the continuous adhesive layer between the face sheet and the core is not interrupted at the ridge-shaped portion of the face sheet.
In a preferred embodiment of the invention, the protrusions of the side frame members are longer in a transverse direction of the panel than a depth of the recessed channels in the transverse direction. Accordingly, when two panels are joined at their respective side frame members with the protrusion of one side frame member fully inserted into the channel of the other side frame member, a gap exists between opposing portions of the side frame members. A portion of a bracket can be inserted into this gap and affixed to the side frame member of one of the panels, and another portion of the bracket that projects out from the panel joint can be affixed to another part of a building structure, thereby attaching the panel to the structure. Such brackets can be used for attaching roof panels to walls and for attaching upper ends of panels to each other and to a ridge member at a ridge of the roof. The brackets thus enable the panels to be attached to the structure without penetrating the face sheets of the panels with fasteners.
A building structure in accordance with one preferred embodiment of the invention has a roof constructed of a plurality of panels oriented such that at least one interlocking panel joint between adjacent panels runs from an outer one of the walls toward a ridge of the roof. A bracket having a plate portion extends into a gap defined between the side frame members forming the at least one interlocking panel joint, and the plate portion of the bracket is attached to one of the side frame members at the panel joint. Another portion of the bracket is attached to another part of the building structure.
Preferably, each panel of the roof runs in a continuous single span from a lower end of the panel adjacent one of the outer walls to an upper end of the panel adjacent the ridge of the roof, and the upper ends of the panels on one side of the ridge and the upper ends of the panels on an opposite side of the ridge are affixed to at least one vertical tension-bearing member that is anchored to the foundation to bear upwardly acting forces exerted on the panels of the roof. The vertical tension-bearing member can comprise an interior load-bearing wall or a series of vertical columns spaced apart beneath the roof ridge. The vertical tension-bearing member preferably is affixed to a ridge member that extends a length of the ridge and is connected to the upper end of each panel of the roof. The panels are connected to the ridge member by the brackets that project from the panel joints.
The roof panels at their lower ends adjacent an outer wall are attached to the outer wall by further brackets that attach to the side frame members in the gaps between adjacent panels. Each bracket has a base portion defining at least one flange portion that is affixed to the wall, and preferably has a pair of flange portions that receive the wall therebetween. The base portion is affixed to the wall by at least one fastener received through the flange portion(s) and the wall. Preferably, the fastener comprises a tube bolt. Tube bolts are preferred over conventional screws because a single tube bolt can provide a joint strength equivalent to a plurality of screws, thus reducing the number of fasteners that must be installed when assembling the structure.
In another embodiment of the invention, a floor of the building structure is constructed of a plurality of panels, each panel having one end attached to one wall and an opposite end attached to an opposite wall of the structure. A floor panel support bracket is affixed to one wall of the building structure so as to extend along the ends of a plurality of adjacent panels, and the ends of the panels are affixed to the floor panel support bracket. The floor can be an upper-story floor of a multi-storied building, the floor panel support bracket bearing loads exerted on the floor. It is preferred that the floor panel support bracket be affixed to the wall by a plurality of tube bolts.
Preferably, the end of each panel that is affixed to the floor panel support bracket defines an outwardly projecting flange that is substantially coplanar with an upper one of the face sheets of the panel, and the flange of each panel rests upon and is affixed to the floor panel support bracket. Alternatively, the lower surface of the panel can rest upon and be affixed to a ledge portion of a floor panel support bracket.
In accordance with yet another aspect of the invention, the walls of the structure comprise a plurality of roll-formed sheet metal members including a plurality of vertical members connected to a plurality of horizontal members, and connections between members are formed by a collar formed on one member and a hole formed through another member, the collar being received through the hole and being bent onto the other member so as to fasten the members together. The walls can be formed in sections that are prefabricated and transported to a job site, and the wall sections can be attached to one another at the job site to form the basic frame of the building. The attachment of the frame sections to one another can be made by tube bolts that are inserted through preformed holes formed in adjoining members of the wall sections.
The invention thus provides a panel and building structure that can be easily and rapidly assembled at a job site. Because many of the components of the structure can be prefabricated in the factory, the flatness, squareness, and dimensional accuracy of the components can be closely controlled, thus facilitating assembly of a structure that is dimensionally accurate, square, and plumb. The building structure of the invention also has high strength, and thus can provide significant advantages over stick-built structures, particularly in terms of resistance to high wind.